If I were to go with less than 5 gallons, I think 3 would be pretty optimal. 32 bottles (if you exactly hit your volume) still feels like you got something out of all the effort, plus you can use 5 gallon kettles, buckets, or even carboys no problem.
3 gallons is exactly what I settled on long ago. In the real world it actually works out to right about 30 bottles. Or a case plus a 6 pack.
I plan all my recipes as 3.5 gallon batches. I collect 4 gallons to start and after the hour boil 3.5 gallons goes in the fermenter so that I actually get 3 gallons of finished beer after losses.
I settled on 3 gallons for several reasons:
- I am the only one in my house who drinks the beer and I don’t go through it as quickly as others might
- I like variety. I don’t want 50 bottles of one beer and 10 cases of beer after brewing 5 batches
- available carboy and keg sizes. I can ferment 3.5 gallons comfortably in a 5 gallon carboy. They make 3 gallon carboys too. I also have several 3 gallon kegs though those are getting harder to find.
- I can brew indoors on my stove, the pot is not too big for the stove to heat.
- I am 60+ and all the containers are smaller, lighter, and easier to handle compared to the “standard” 5 gallon batch, which will now start to matter more.
The biggest downside of the smaller batches is that I no longer have the capacity to brew 5 gallons, so if I want to fill a 5 gallon keg then I need to brew twice or plan a concentrated batch to be watered down after the boil.
For newbies, extract is the easiest way to start out. Working with known gravity points per pound of extract. The big pot is the biggest expense. I have a 5 gallon Anvil pot. Buy quality, buy once, cry once.
The learning curve is the biggest thing. So many hops now, many of us experirenced brewers have not brewed with half the varieties out there. Learning all the grains and what they are for. Learning all the beer styles and how to come up with recipes. Some kind of recipe software is great to have.
+1 on extract for newer people - its simpler, and you want to have the best chance for a positive experience early on so a new person doesn’t get quickly discouraged.
Far as cheap, nothing is cheap today. Extract costs more than grain but the work is done for you and your brew day becomes 2 hours shorter. Your time is worth something too.
Mead is also a good thing to start with. You don’t need a pot since you don’t boil mead. But even making cider or mead now has gone way up. I used to get 5 lbs of honey for $11.99 about 2 years ago and that is $21.99 now.